P3.01-019 Desmoplasia is Associated with Poor Prognosis and Carcinoma-Associated Fibroblast Heterogeneity in Non-Small Cell Lung Cancer: Topic: Morphology

Abstract

Cancer-associated fibroblasts (CAFs) are known to influence tumor development, progression and metastasis. Their characteristics and prognostic role in non-small cell lung cancer (NSCLC) patients have been recognized. However, the functional heterogeneity of CAFs between patients and its genetic basis is less understood. Two pathologists scored for desmoplasia on Hematoxylin-Eosin stained sections of resected lung tumors from two patient cohorts: one consisting of 171 NSCLC patients (128 adenocarcinoma, 43 squamous carcinoma) and the second of 24 primary cultures of CAFs. Percent area of desmoplasia among total tumor stroma was used to define high desmoplasia (HD) versus low desmoplasia (LD). The desmoplasia and survival analysis were assessed for 171 NSCLC patients. Gene expression data on RNA extracted from CAFs in contracted gels following 24 hours incubation was obtained using Illumina Human HT-12v4 Bead Chips array and was preprocessed and normalized using RMA and values were log2 transformed. Significant genes whose expression is strongly correlated (Spearman correlation coefficient and p value) with percent of desmoplasia were identified in both cohorts. The gene set enrichment analysis (GSEA) was applied to test for the enrichment of CAF cohort significant genes in 171 NSCLC cohort. Additionally, CAF significant genes were subjected to pathway enrichment analysis using Pathway Data Integration Portal ver. 2.5 (http://ophid.utoronto.ca/pahtDIP). The prognosis of adenocarcinoma patients with HD had poorer outcome in comparison to the patients with LD (disease free survival at 3 years 34% vs. 75% p=0.00045 and relapse rate 41% vs. 14%, p=0.0051). In the CAF cohort, the number of genes that are significantly associated with desmoplasia for enrichment are 356. Using GSEA, these genes were enriched in 171 NSCLC cohort (with a p value of 0.045). Protein-protein interaction (PPI) partners of these 356 genes were acquired using Integrated Interaction Database – IID (version 2016-03, http://dcv.uhnres.utoronto.ca/iid/). Obtained genes were then ranked according to their degree, i.e., number of PPIs. Top 44 (top 1%) of the genes were then selected to pathway enrichment analysis using pathDIP version 2.5. 245 pathways that significantly enriched by these 44 genes (FDR < 0.01) were obtained. Many of these pathways are known to be involved in lung cancer. We demonstrated that the prognosis of lung adenocarcinoma patients with HD had poorer outcome in comparison to the patients with LD. Furthermore, PPI analysis of CAF genes associated with HD reveals enrichment of many cancer-related pathways, suggesting their high relevance to lung cancer.